Agent for protecting polyamide fibers or threads against the attack of bleaching and washing baths

ABSTRACT

WHEREIN R and R1 are selected from hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms in the chain, and salts thereof.   Polyamides may be protected during washing or bleaching by applying thereto a compound of the formula:

I2 1 1 1 1 l l Karl Dithrnar Eschershelmer, Landltrasse 529; Peter Koblischek, Parkstrlsse 15, both 01 FnnkIurt/Mlln, Germany 754,760

Aug. 23, 1968 Dec. 21, I971 Deutsche Gold-und Silber- Scheideanstalt Vormals Roessler Aug. 26, 1967 Germany Inventors Appl. No. Filed Patented Assignee Priority Int. Cl D061 3/02 [50] Field oISearch 8/111, 133; 252/102; 117/138.5

Primary ExaminerMayer Weinblatt Auorney- Beveridge & De Grandi ABSTRACT: Polyamides may be protected during washing or bleaching by applying thereto a compound of the formula:

R-NH-C-NH-G-NHR:

wherein R and R, are selected from hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms in the chain, and salts thereof.

The invention relates to the use of biguanides for the protection of polyamide fibers or threads against the attack of bleaching baths containing active oxygen compounds.

German Pat. No. 1,025,376 discloses that N-phenylbiguanide protects polyamide fibers against the attack of peroxide containing bleaching and washing agents. Although this fiber protecting effect is significant, a disadvantage has arisen in the course of years of use. Small amounts of iron and manganese salts are present in the water of bleaching baths, or also-as for example manganese lactate-are added in certain amounts to the polyamide fibers during their manufacture for the purpose of light protection. These iron and manganese saits react with N-phenylbiguanide to produce discolorations which are undesirable, especially in bleaches. As the use of manganese compounds for light protection in polyamide textiles now has become increasingly common, the disadvantages of discoloration are a drawback in spite of the good fiber protection provided by N-phenylbiguanide.

It is possible that the known tendency of the biguanides to form complexes with metal salts [see for example SLOTIA, Berichte der Deutchen Chemischen Gesellschaft 62, 1390 l929)]could be the cause of this behavior.

Surprisingly we have found that certain compounds of the biguanide series which, although they can form metal complexes, do not show the drawback of the discoloration. By the addition to peroxide bleach mixtures at the same bleaching duration and also in the presence of iron or manganese c'ompounds under otherwise identical conditions, they produce white values of about 85 percent where, according to German Pat. No. 1,025,376, only barely 80 percent white are obtainable. This increase in whiteness is of great importance, because a difference of only 1 percent is plainly noticeable to the eye.

German Pat. No. 1,025,?! 76 concerns a biguanide substituted in first position by the phenyl group. The first and fifth positions are here equivalent.

In accordance with this invention, polyamide fibers, threads or textiles are protected against the attack of bleaching and washing baths containing active oxygen compounds, while obtaining improved whiteness, by using a biguanide compound of the fonnula:

wherein R and R are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, and substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.

If the unsubstituted biguanide is used, a good filament protective action and a good white effect are found:

lf substitution is made in the first position or in the fifth position with a methyl, ethyl, propyl, isopropyl, butyl, heptyl, hexyl, and/or cyclohexyl group, a good filament protective action and a good degree of whiteness are observed:

A good fiber protection and a good white value also result if each alkyl or cycloalkyl group is in the first and fifth positions of the biguanide molecule:

Several alkyl substituents on one of the end position amino groups influence the fiber protective action according to the process detrimentally. if this kind of substitution is present with further alkyl groups, the fiber protecting action ceases, as for example with l,5-tetraalkylbiguanide. In general, it can be stated that monoor disubstituted derivatives and their salts (analogously each biguanide unit in macrobiguanides) are effective in the sense of the invention.

On their part, the alkyl groups can also be substituted, thus for example consisting of CH,Cl groups. Also, the fiber protective action and the white effect are not detrimentally influenced to any extent thereby. The alkyl groups can on their part also, for example, be substituted by a further biguanide group.

If the biguanide molecule is substituted in second position, however, the fiber protective action will then be nullified, whereby the substances will become useless as additives to peroxide containing bleaching baths for polyamide fibers. The imine and the secondary amino groups must therefore be unsubstituted if an optimum efi'ect is to be obtained.

lf instead of alkyl or cycloalkyl groups, the end position N- atoms are substituted with phenyl groups, then the fiber protective action will not be detrimentally affected, but the degree of whiteness of the polyamide fibers bleached with this additive will be decreased. Thus, in addition to the N-phenylbiguanide mentioned initially, or l-phenylbiguanide, the 1,5- diphenylbiguanide is also not usable in the sense of the present invention. The same is true for phenyl groups substituted on their side, thus for example alkylphenyl or alkylaryl groups.

The invention therefore involves an active agent, based on biguanides for the protection of polyamide fibers, polyamide threads or polyamide textiles against attack by bleaching and washing baths containing peroxide compounds, which active agent is biguanide or its derivatives substituted in first and/or fifth position with alkyl groups with one to six carbon atoms or with the cyclohexyl group, or the salts of the said biguanides or mixtures of the said compounds, or which contains these compounds as active components, on the condition that all amino or imino groups of the biguanide grouping still carry one hydrogen atom.

The aliphatic or cycloaliphatic groups being in first position and/or in fifth position can in turn be substituted, for example by chlorine or also by a further biguanide grouping so that for example a dibiguanide results.

These agents can suitably be used together with peroxide compound or active oxygen producing compounds and the additives commonly useful in bleaching or washing, such as pl-l regulators, wetting, emulsifying, stabilizing, finishing and optical brightening agents. But they can also be applied as pretreatment to the fibers or threads prior to the action of the bleaching or washing baths.

In order to take into consideration high-hydrogen peroxide concentrations common in recent times for the impregnation bleach and in order to obtain plainly recognizable differences in fiber protection effect, very strong hydrogen peroxide baths with 30 cc. commercial 35 percent 11,0, per liter bleaching bath were brought into action on bleach sensitive polyamide fibers in the following examples and comparisons. Thus, also the dose of the fiber protective agent, of which as little as l/lO of a gram per liter suifice with only 10 cc. 35 percent hydrogen peroxide for the polyamide fiber protection, had to be increased to 1 gram fiber protective agent per liter.

The above-mentioned compounds fumishing fiber protection are bases. Instead of the bases, their salts can also be employed with success, for example preferably their salts with sulfuric acid or hydrochloric acid, but also the salts with tartaric acid or short chain organic acids with up to four carbon atoms. By the use of these salts of the biguanide charge weight in the following analyses was adjusted to 1 gram per liter of the free base. In the agents according to the invention, occasionally two or more, i.e., mixtures of the compounds, thus biguanide, its derivatives and the salts of the bases with organic or inorganic acids can be employed in order to effect the desired fiber protection on all forms of textiles from polyamide.

The stabilization of the baths was carried out in the usual manner with water glass and magnesium sulfate. The fiber protective effect obtained was measured through detennination of the resistance to tearing of the bleached polyamide fiber textiles measured before and after bleaching. whereby, also, the strength of the polyamide fiber textiles that had been bleached without fiber protective agent under otherwise equal conditions was measured and compared.

The degree of whiteness of the textiles (fabric) was always distinguished with the Zeiss-Elrepho step photometer with filter 6 and white standard 565 as percent on the whiteness degree scale.

To a part of the bleaching baths, 1 mg. manganese or iron in salt form was added per liter each time.

The bleaching damage to the polyamide fibers without the addition of fiber protective agent is very considerable in samples from all origins, but nevertheless varied in degree here and there. Therefore, one sample was chosen from each of the two fiber-types 6 and 6,6 polyamide of high-bleach sensitivity 30 and also high-strength loss in ,0, bleach. Optical brighteners were not used in the tests.

For the examples 6.6polyarnide was preferably used because this according to experience is somewhat more difficult to bleach than 6-polyamide (Perlon EXAMPLE I The fiber protection effect of the biguanides mentioned below was ascertained on 6,6-polyamide fabrics in a bleaching bath of the following composition:

(H g. magrteium sulfate per 1.0 cc. waterglas 38' Be liter 30.0 cc. hydrogen peroxide 35% by weight distilled l.0 g. fiber protective agent water the pH value was adjusted with soda lye to 10.2.

Bleaching conditions Active oxygen content 5.6 g./l. Temperature 90' C. Bleaching time 2 hours Bath ratio 1:50 Test material 6.6 polyarnide (nylon,

4on3 mat Tearing strength untreated l8l.5 g.

The tearing strength was ascertained in standard climate at 20 C. and 65 percent rel. air moisture and is the average of individual values.

The percentages indicated in the table state the loss relative 60 to the initial value.

Tear Loss, Fiber protective agent strength, g. percent 65 According to invention:

(a) Blguanlde 165. 8 8. 7 (b) 1methyl-bigllanide.... 166.8 8. 1 (c) 1-n-propy1-biguanide. 167. 9 7. 5 (d) l-isopropyl-biguanlde... 160. 1 11. 8 (e) 1-n-hexyl-biguanide 167. 7 7. 6 70 (i) Lcyclohexyl big'uanlde.. 163. 7 ll. 8 (g) 1,5-dimethyl biguanide- 163. 3 15.5 For comparison:

one 59. 3 67. 3 l-phenyl biguanide 165. 9 8.6 -dimethyl biguanide- 128. 2 29. 4 1,2-dlrnethyl blguanide 110. 1 30. J 75 EXAMPLE 2 5 under equal conditions as in example l, analogous values are obtained.

A 6-polymide, 45/9 mat. with an initial strength of 242.3 g. has after bleaching as described in example 1, without fiber protective agent, only a tearing strength of 58.5 g; that is a loss of 75.9 percent relative to the strength before bleaching.

If, on the other hand, for example, an agent according to the invention, based on l-methyl biguanide is added to the bleaching bath, the tearing strength after the bleaching amounts to 220.0, that is a loss of only 9.2 percent.

EXAMPLE 3 The improvement of the agents claimed according to the invention, respectively of their effective substance in comparison with l-phenyl biguanide according to Gennan Pat. No. 1,025,376, is demonstrated by measurement of the degree of whiteness of a fabric of 6,6-polyamide.

The bleaching bath had the following composition:

0.l g. magnesium sulfate per l.0 cc. water gla- 38 Be liter 30.0 cc. hydrogen peroxide 355 by weight distilled 1.0 llber protective agent water The bleaching conditions were:

Active oxygen content 5.6 |./'l. Temperature C. Bleaching time 2 hours Bath ratio l:50

The degree of whiteness of the untreated 6,6-polyamide fabric was 80.5 percent white.

in the presence of iron and manganese there was added to the bleaching bath per liter of mixture 0.0049 g. FeCl, 6 H,O 0.001 g. Fe l p.p.m. or 0.0036 g. MnCl, 4 H,O= 0.00l g. Mn= l p.p.m. The results of the whiteness detenninations were:

The results are for better demonstration illustrated graphically in the attached diagram.

EXAMPLE 4 Analogous with the testing conditions of example i and also with the use of the same 6,6polyamide, the fiber protecting effect of a dibiguanide, prepared from a diamine and dicyanamide, was detennined.

1.1-othylene-dl-biguanldo I ll If 1.0 g. l,l 'ethylenc-di-biguanide is added to the bleaching bath as fiber protecting agent, the tearing strength after the beaching amounts to 163.2 g., that is a loss of 10.1 percent.

The degree of whiteness was 83.5 percent (without metal addition to the bleaching bath) and was lowered only by 0.5 percent on the white scale by the addition of iron or manganese salts (analogous to example 3).

The examples show that with the agents according to the invention, in spite of the intentionally chosen harsh bleaching conditions, which bring a large excess of hydrogen peroxide into action, a very efi'ective fiber protection can be obtained. By comparison of the tearing strengths of the 6,6-polyamide fiber fabrics bleached without and with fiber protective agent in example I, it is found that the strength loss without fiber protective agent amounts to 67.3 percent. Through the new agent according to example 1 with the compounds 0 to g, this loss of 67.3 percent average is pushed back to less than percent. With not excessively harsh bleaching conditions without excess l-l,0,, a decline in peroxide strength loss through the new agents down to the limit or the error of measurement is recorded. Therefore, practically complete fiber protection is obtained against bleaching baths containing active oxygen compounds, because damage in bleaching baths containing other percompounds, as for example sodium peroxide, sodium perborate, or other known peroxidic bleaching agents, also is practically completely prevented.

What is claimed is:

l. A method for protecting polyamide fibers, threads, or textiles against the attack of bleaching and washing baths containing active oxygen compounds comprising applying to said polyamide a compound of the formula:

wherein R and R, are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.

2. The method as defined in claim 1 wherein said substitution is chlorine or a biguanidyl group.

3. A polyamide fiber, thread, or textile coated with a compound of the formula:

wherein R and R, are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.

4. A polyamide as defined in claim 3 wherein said substitution is chlorine or a biguanidyl group.

5. ln a method for bleaching or washing polyamide fibers, threads, or textiles in a bath containing an active oxygen compound in which a biguanidine derivative is incorporated into the bath, the improvement for protecting said polyamide against loss of strength while obtaining improved whiteness comprising incorporating into said bath a compound of the formula:

wherein R and R, are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.

6. The method as defined in claim 5 wherein said substitution is chlorine or a biguanidyl group.

7. A composition for protecting polyamide fibers, threads, or textiles, against loss of strength while obtaining improved whiteness during washing or bleaching said polyamide, said composition consisting essentially or an active oxygen compound and a compound of the formula:

wherein R and R, are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.

8. A composition as defined in claim 7 wherein said substitution is chlorine or a biguanidyl group.

i t i i 

2. The method as defined in claim 1 wherein said substitution is chlorine or a biguanidyl group.
 3. A polyamide fiber, thread, or textile coated with a compound of the formula: wherein R and R1 are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salTs thereof.
 4. A polyamide as defined in claim 3 wherein said substitution is chlorine or a biguanidyl group.
 5. In a method for bleaching or washing polyamide fibers, threads, or textiles in a bath containing an active oxygen compound in which a biguanidine derivative is incorporated into the bath, the improvement for protecting said polyamide against loss of strength while obtaining improved whiteness comprising incorporating into said bath a compound of the formula: wherein R and R1 are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.
 6. The method as defined in claim 5 wherein said substitution is chlorine or a biguanidyl group.
 7. A composition for protecting polyamide fibers, threads, or textiles, against loss of strength while obtaining improved whiteness during washing or bleaching said polyamide, said composition consisting essentially or an active oxygen compound and a compound of the formula: wherein R and R1 are hydrogen, alkyl groups having one to six carbon atoms, cyclohexyl, a substituted cyclohexyl group, a substituted alkyl group having one to six carbon atoms, and salts thereof.
 8. A composition as defined in claim 7 wherein said substitution is chlorine or a biguanidyl group. 